An on-duty Chicago Police officer was shot in the arm as he tried to break up a fight between suspected gang members on the West Side Monday, police said.

Investigators said it didn't appear that the shooter -- who had not been captured late Monday -- was aiming for the officer.

The officer was in good condition at Northwestern Memorial Hospital, said Chicago Police Deputy Supt. Charles Williams.

"His spirits are good," Williams told reporters gathered at the site of the shooting near Division and Campbell. Police were not releasing the injured officer's name, but Williams said he was a patrol officer assigned to the 14th District.

NEIGHBORS 'USED TO' GUNSHOTS

The incident occurred just before 3 p.m. The officer and his partner approached two groups of teens, Williams said. Witnesses reported hearing four to six shots and then seeing the teens scatter, with most running east on Division. The police officers did not return fire, Williams said.

One witness, who works in a nearby business and did not want his name used, said: "I heard the shots, but I was in the kitchen. I wasn't about to go out and see. . . . It's not the first time [hearing gunshots]. We're used to it. We know when you hear it, you throw yourself on the floor."

In October, police officers trying to stop a gang-ordered execution fatally shot two men and wounded a third in Humboldt Park after one of them pointed an AK-47 semiautomatic rifle at officers.